The present invention relates to a golf club head having face line grooves in the surface of a club face for hitting a golf ball, and more particularly to a golf club head having an improved dischargeability of foreign matters from the face lines without impairing the frictional force with a ball. The present invention also relates to a method for producing such a golf club head having an improved dischargeability of foreign matters from the face lines.
A plurality of narrow grooves extending in a toe-heel direction, i.e., face lines, are formed at intervals in the surface of a ball-hitting face of a golf club head in order to enhance the frictional force with a golf ball. These face lines can enhance the frictional force between the face and a ball by the edges thereof, thus imparting a sufficient back spin to the ball.
On the other hand, foreign matters such as water, mud, grass, a cover material of golf ball and so on may be caught in the face lines during playing. If a golf ball is hit by a golf club head in such a state that foreign matters are caught in the face lines, the frictional force between the face and the ball is decreased, so the amount of back spin is decreased and the flight distance gets unstable. In particular, in case of iron-type golf clubs for which stable flight distance is important, especially a short iron used for short approaches to the green, unstable flight distance is a serious problem. A golf club head capable of effectively removing foreign matters caught in the face lines is proposed for instance in JP 2007-301017 A.
It is known to impart a rough surface to the face of golf club heads by impingement of metal grains onto the surface of the face, as disclosed for example in JP 2001-321469 A.
It is an object of the present invention to provide a golf club head capable of easily discharging foreign matters caught in face line grooves while sufficiently securing a frictional force generating at the time of hitting a golf ball.
Another object of the present invention is to provide a method for producing a golf club head having an improved dischargeability of foreign matters from the face lines without lowering the frictional force between the face and a golf ball.
These and other objects of the present invention will become apparent from the description hereinafter.